So it looks like I'm going ahead with the turbo build so I thought I'd start a new thread, for completeness the 172 swap is here : https://www.rtoc.org/boards/showthread.php?t=5149
I'm looking for a low boost standard compression build the type we've seen many times before, using a cast manifold, and the GT28R I used to do the 11.5x second 120mph runs in 2005
There isn't much space up front in the Twingo and I didn't think I could get an intercooler in and would have to use a charge cooler, but even with a CC there is a lot of stuff to find homes for. Anyway, a look on Ebay and a quick measure brought up a bar and plate intercooler 550x140x65 complete with a bunch of pipes, hoses, and clips, what's not to like?
Anyone who knows me knows that I like to measure stuff, intercoolers and pipes need to be measured.
The box of bits turned up today, and at first glance it all looks reasonable for the money, the pipes have swaged ends and mandrel bends.
First bit of bad news is that the hoses are 60mm ID and the pipes 57mm OD, they don't have much chance of sealing, I'll point this out to the seller, but whatever happens I won't use them.
On to the testing, but first some numbers - please point out any errors I make.... My best guess is that to make 230hp the engine will be pumping about 300CFM (cubic feet per minute) of air. That's a rough number but it shouldn't be massively out. A good intercooler will have less than 1psi pressure drop across it, but I believe that anything under 2psi will be fine.
** not bad, all imperial units so far, I have a nasty habit of mixing them**
***apart from the IC dimensions that is***
My flow bench https://www.rtoc.org/boards/showthread.php?t=17946
now Henry is a smart chap, and when it comes to dust and crap he can hold his head high, he struggles a bit with flow testing big pipes so the accuracy isn't as good, but he still does OK.
I put a 172 throttle body on the bench first to get a feel for things, I get ~310CFM at 10" H2O. Now, without trying to teach granny about eggs I should explain how this CFM number differs from the 300CFM engine flow I mentioned earlier. On first view one might see that 310 was bigger than 300 and thus all is good in the world. All is good in the world, but not for that reason. The 300CFM engine flow is the amount of air the engine will be pumping at full power. The flow test for the throttle says that when it is flowing 310CFM there will be 10" H2O (0.36psi) pressure drop across it. This is fine.
The next thing I tested was one of the 600mm long 2.25" pipes, it flowed 240CFM @10", adding a second one dropped that flow to nearer 220CFM. I then tried a single 90deg bend of the same 600mm length, it showed ~235CFM. Nothing wrong with those bends. If a full pipe flowed 200CFM it'd have a pressure drop around 0.8psi at full power, seems Ok to me.
The final thing to test was the intercooler, I was quite casual doing the test, the 57CFM was a shock. If my measurement is correct, and my maths is right that'll have something like a 10psi drop across it at full power. This is where I start getting nervous, surely that can't be right????
A quick look around the internet fails to confirm my findings, in fact, most results seem more like I'd expect.
I did however find this http://www.myaudis4.com/amd-ic-flow-test/ note that he tests at 28"H2O, so you have to multiply my results by 1.67 to compare.
I'm not sure where to go from here, it seems madness to use the intercooler if it is that bad, but maybe I'm wrong and need to test it on the car??
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Originally Posted by Mart
I remember looking at the clutch before I fitted the engine, it looked perfect then.
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